Laserfiche WebLink
Material: Alluvial groundwater (approximately 8 mg/L dissolved uranium). <br />Two-inch Pipe investigation: Pipe Joint Separation at Exploratory Core Hole Casing <br />Date/Time: September 29 - October 7, 2010 <br />Description: A pipe joint separated at a 2-inch diameter exploration core hole casing <br />during identification and plugging investigation work. Groundwater <br />flowed out of the separated pipe casing underneath the old emergency <br />storage pond area at an estimated rate of 20 gpm. The release was <br />contained below and within the pond, ultimately infiltrating into the <br />alluvium and did not flow overland into Ralston Creek. About 4-6 <br />weeks following the release, water quality monitoring data indicated <br />that the released slug of elevated groundwater began arriving at <br />groundwater collection sumps (Sump 4, MW-9, Sump 1) where <br />captured water was pumped back to the water treatment plant for <br />treatment. <br />Corrective Actions: October 2, 2010 - Water was pumped from the pond up to the concrete <br />Barrens Ponds and underlying alluvial fill was excavated to locate the <br />leaking end of the core hole casing pipe. <br />October 7, 2010 - The casing pipe end was located and flow was <br />stopped by attaching a rubber coupling to the pipe end and flexible <br />HDPE pipe. The HDPE pipe was then raised up the pond embankment <br />to an elevation sufficient to stop flow. A mechanical expansion plug <br />was placed at the end of the HDPE pipe as a secondary containment <br />measure. <br />Quantity: Estimated 230,400 gallons (to alluvium and old emergency pond). <br />Material: Groundwater from an unknown source (approximately 25 mg/L <br />uranium, 1.5 pCi/L Ra-226). Although believed to be in hydraulic <br />connection to the flooded mine workings, the geochemistry of this <br />groundwater is different than that of water in the flooded mine workings <br />(approximately 34 mg/L uranium, 245 pCi/L Ra-226). <br />Water Treatment Plant Tank Oven flow <br />Date/ Time: <br />Description <br />October 13-14, 2010 <br />Sediment produced by construction activities reached a groundwater <br />collection sump and ultimately clogged a cone filter in the water <br />treatment plant, resulting in the shutdown of a building system pump <br />and subsequent surge tank overflow. The run-permissive systems <br />2